Biomedical electron microscopy at the University of Southern California is almost exclusively centered at the School of Medicine in the electron microscopy facilities of the Department of Anatomy and Cell Biology. For almost 25 years, the Department has had active research programs utilizing electron microscopy as the primary investigative tool. In addition, faculty from other departments of the USC School of Medicine rely upon the facilities and expertise of the Department of Anatomy and Cell Biology for the ultrastructural portions of their NIH-funded research. Over the last 8 years more than a dozen NIH grants, and a like number of NSF and private grants, have required the use of the microscopes housed in the Department of Anatomy and Cell Biology. However, the passage of time has led to increased numbers of highly qualified researchers using instruments which are obsolete or becoming increasingly unreliable. The AEI-6B electron microscope purchased in 1968 has reached the end of its useful life because of frequent servicing, lack of parts, and excessive down time. The current demand for electron microscopic studies and the increased service problems with present instruments necessitates the purchase of a new microscope to replace the obsolete AEI-6B. In addition, funded NIH grants in progress indicate an increased demand for electron microscopy. Without updating the electron microscope facilities of the Department of Anatomy and Cell Biology, a major research asset of the University of Southern California will be lost.